As is common in causally consistent data stores [1]}, [2]}, [3]}, to
ensure that causal transactions execute on consistent snapshots, a data center
exposes a remote transaction to clients only after exposing all its
dependencies. Then to satisfy the Eventual Visibility property under failures, a data
center receiving a remote causal transaction may need to forward it to other
data centers, as in reliable
broadcast [4]} and anti-entropy protocols for replica reconciliation [5]}.
